1. Technical Field
This disclosure generally relates to thermal fuses, relays, and other electrical components (collectively referred to herein as “circuit” or “electronic” implements) adapted for use in and modifying at least one characteristic of a circuit; and more particularly, to a circuit implement that utilizes shape memory material actuation to effect functionality.
2. Background Art
Fuses, relays, and variable resistors, as well as other components have long been implemented in electronics to improve the safety and capabilities of circuits. For example, thermal fuses are often used to protect vital or expensive components, people, and environments from current and thermal overloading; and relays are often used to enable a low-energy input device such as the ignition in a vehicle to actuate a high-energy device such as a starter motor.
With respect to fuses, it is appreciated that traditional fuses offer permanent interruptions to devices that may otherwise require only temporary protection. Moreover, these fuses are increasingly difficult to replace as devices become increasingly complex and congested. As a result, manually and autonomously resettable fuses have been developed, including, for example, polymeric positive temperature coefficient (PTC) These fuses re-orient the polymer chains from crystalline to amorphous, reducing current flow to a nearly “open state,” when subjected to excessive current. Concernedly, however, PTC fuses never actually open the circuit, and because they create resistance on a molecular level, their reset functionality may be difficult to control.
With respect to relays and variable resistors, a simple, inexpensive, and reliable construction is often desirous and/or beneficial. However, most relays known in the art are electromechanical, and often constructed with a complex metal coil and armature that is susceptible to getting stuck after repetitive use. In addition, the application and removal of the induction current to the coil often requires the use of additional electrical components to dissipate unwanted or damaging energy influx. Other relays known in the art eliminate the need for electromechanical devices, but incorporate numerous electrical components, increasing cost. They are also prone to false firing and shorting out.